Alexander Kekulé, Director of the Institute for Medical Microbiology of the University Hospital Halle (Saale), has written an article in the ZEIT from 08.11.2018 – online behind the payment barrier – “Hysteria around the wrong thing. the limit of 40 micrograms for the exhaust gas is taken from the air”. To be read as facsimile on http://www.gegenwind-saarland.de/Klimawandel/181108-ZEIT-Hysterie-um-NO2.mrkd.pdf-Hysterie-um-NO2.mrkd.pdf . A shortened version was published in the Tagesspiegel of 10.11.2018, but no longer available on the online page of the TAGESSPIEGEL, but only via PRESSREADER. https://www.pressreader.com/germany/der-tagesspiegel/20181110/281715500636547
Subsequently, in 1993, the EU decided to set long-term air quality objectives, including a strict NO limit value. The legitimacy of such a value had to be based on the work of the World Health Organization (WHO). In order to reduce the then valid WHO guideline value of 150 micrograms, a working group was formed there, which made use of a meta-analysis from a five-year older report by the US Environmental Protection Agency. According to Kekulé, the meta-analysis evaluated various research projects whose parameters were completely different. Despite these completely different influencing factors, the result was “that respiratory diseases are 20 percent more frequent in households with gas cookers than in households with electric cookers”. However, no measured values could be derived from this, as very different concentrations (8 – 2500 micrograms) were found in households with gas cookers. “In the absence of useful data, the experts estimated without further ado that a gas stove increases the mean annual NO concentration in the household to about 40 micrograms and suggested this value as a guideline. To date, there is no evidence that the figure has anything to do with the health effects of NO”. Without verifying this, the EU adopted it as the legal limit. “To date, there are no robust data supporting the 40 microgram limit.”